Compilare: user.cpp: In function ‘void solve()’: user.cpp:42:17: warning: unused variable ‘lo’ [-Wunused-variable] int l,r,mid,lo,hi,s; ^ user.cpp:42:20: warning: unused variable ‘hi’ [-Wunused-variable] int l,r,mid,lo,hi,s; ^ user.cpp: In function ‘int main()’: user.cpp:71:10: warning: unused variable ‘i’ [-Wunused-variable] int n,k,i; ^ user.cpp:69:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("virus.in","r",stdin); ^ user.cpp:70:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("virus.out","w",stdout); ^